| 1. |
- Castro-Giner, F., et al.
(author)
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Joint effect of obesity and TNFA variability on asthma : two international cohort studies
- 2009
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In: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 33:5, s. 1003-1009
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Journal article (peer-reviewed)abstract
- Obesity is a risk factor for asthma. Adipose tissue expresses pro-inflammatory molecules including tumour necrosis factor (TNF), and levels of TNF are also related to polymorphisms in the TNF-alpha (TNFA) gene. The current authors examined the joint effect of obesity and TNFA variability on asthma in adults by combining two population-based studies. The European Community Respiratory Health Survey and the Swiss Cohort Study on Air Pollution and Lung and Heart Disease in Adults used comparable protocols, questionnaires and measures of lung function and atopy. DNA samples from 9,167 participants were genotyped for TNFA -308 and lymphotoxin-alpha (LTA) +252 gene variants. Obesity and TNFA were associated with asthma when mutually adjusting for their independent effects (odds ratio (OR) for obesity 2.4, 95% confidence interval (CI) 1.7-3.2; OR for TNFA -308 polymorphism 1.3, 95% CI 1.1-1.6). The association of obesity with asthma was stronger for subjects carrying the G/A and A/A TNFA -308 genotypes compared with the more common G/G genotype, particularly among nonatopics (OR for G/A and A/A genotypes 6.1, 95% CI 2.5-14.4; OR for G/G genotype 1.7, 95% CI 0.8-3.3). The present findings provide, for the first time, evidence for a complex pattern of interaction between obesity, a pro-inflammatory genetic factor and asthma.
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| 2. |
- Cerveri, I, et al.
(author)
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What defines airflow obstruction in asthma?
- 2009
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In: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 34:3, s. 568-573
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Journal article (peer-reviewed)abstract
- Asthma guidelines from the Global Initiative for Asthma (GINA) and from the National Heart, Lung, and Blood Institute provide conflicting definitions of airflow obstruction, suggesting a fixed forced expiratory volume in 1 s (FEV(1))/forced vital capacity (FVC) cut-off point and the lower limit of normality (LLN), respectively. The LLN was recommended by the recent American Thoracic Society/European Respiratory Society guidelines on lung function testing. The problem in using fixed cut-off points is that they are set regardless of age and sex in an attempt to simplify diagnosis at the expense of misclassification. The sensitivity and specificity of fixed FEV(1)/FVC ratios of 0.70, 0.75 and 0.80 versus the LLN were evaluated in 815 subjects (aged 20-44 yrs) with a diagnosis of asthma within the framework of the European Community Respiratory Health Survey. In males, the 0.70 ratio showed 76.5% sensitivity and 100.0% specificity, the 0.75 ratio 100.0% sensitivity and 92.4% specificity, and the 0.80 ratio 100.0% sensitivity but 58.1% specificity. In females, the 0.70 ratio showed 57.3% sensitivity and 100.0% specificity, the 0.75 ratio 91.5% sensitivity and 95.9% specificity, and the 0.80 ratio 100.0% sensitivity but 72.9% specificity. The fixed cut-off points cause a lot of misidentification of airflow obstruction in young adults, with overestimation with the 0.80 ratio and underestimation with the 0.70 ratio. In conclusion, the GINA guidelines should change their criteria for defining airflow obstruction.
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| 3. |
- Svanes, C, et al.
(author)
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Long-term reliability in reporting of childhood pets by adults interviewed twice, 9 years apart. Results from the European Community Respiratory Health Survey I and II
- 2008
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In: Indoor Air. - : Hindawi Limited. - 0905-6947 .- 1600-0668. ; 18:2, s. 84-92
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Journal article (peer-reviewed)abstract
- Investigation of long-term effects of childhood pet exposure is usually based on retrospective information provided by adults, while there is little knowledge about the reliability in adult reporting of childhood events. We analyzed 8287 adults interviewed about childhood pets twice, on average nine years apart, in the European Community Respiratory Health Survey. Agreement between the surveys in reporting of childhood cats, dogs and birds were investigated with kappa statistics, and potential effects of disease status on agreement were analyzed with kappa statistics and multiple logistic regressions. Cats, dogs and birds in childhood were reported by 44, 41 and 38%, respectively. Cohen's kappa for agreement in adult reporting of childhood pets was 0.714 (95% CI=0.698-0.729) for cat, 0.709 (0.691-0.722) for dog, and 0.606 (0.591-0.626) for bird. Thus, agreement was significantly higher for reporting of cat and dog than for bird. Adult wheeze, asthma or atopy did not influence agreement. Neither did adult cat sensitization influence agreement in adult reporting of childhood cat. Childhood factors such as moving house <5 years, or growing up as a single child, in a large family or in a rural area, were associated with poorer agreement, while adult factors were unrelated to agreement. PRACTICAL IMPLICATIONS: Long-term reliability in adult reporting of childhood pets was substantial, and not influenced by disease status. Thus, collection of information about childhood pets from adults appears to be reliable for the purpose of studying adult allergic disease. Future studies should consider that the reliability was higher for a more important childhood event and influenced by childhood rather than adult characteristics. Imperfect reliability contributed to underestimation of the effects of pets on adult allergy; i.e. with a kappa of 0.71, a true odds ratio (OR) of 0.80 would be attenuated to 0.86. Future studies should account for non-differential misclassification error.
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| 4. |
- Harrop, J., et al.
(author)
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Eczema, atopy and allergen exposure in adults : a population-based study
- 2007
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In: Clinical and Experimental Allergy. - : Wiley. - 0954-7894 .- 1365-2222. ; 37:4, s. 526-535
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Journal article (peer-reviewed)abstract
- Background: There are few published studies on geographical variation in prevalence of eczema in adults or its association with recognised risk factors for allergic disease. Objective: To describe the geographical variation in prevalence of eczema in adults, assess the associations with sociodemographic risk factors, serum-specific IgE and IgG, and exposure to allergen. Methods: A community-based sample of 8206 adults aged 27-56 years, in 25 European centres and Portland, USA, provided questionnaire information on symptoms of eczema. Serum-specific IgE to house dust mite (HDM), cat, grass and Cladosporium, and IgG and IgG4 to HDM and cat were measured. Mattress levels of mite and cat allergen were assessed. Results: Overall prevalence of eczema was 7.1% (range between countries of 2.2-17.6%). Eczema was associated with female gender [odds ratio (OR) 1.25; 95% confidence interval (CI) (1.01-1.55)], family history of atopic disease (OR 1.43; 95% CI 1.18-1.74), IgE sensitization to at least one allergen (OR 1.50; 95% CI 1.19-1.90), particularly Cladosporium (OR 3.65; 95% CI 1.81-7.37), and total IgE. Eczema was negatively associated with age and no clear associations were observed with sibship size, mattress mite and cat allergen levels or with cat and HDM-specific IgG or IgG4. Conclusions: There is geographical variation in the prevalence of eczema in adults both within and between countries. Although the disease is associated with IgE sensitization, in this study it was not related to mattress mite or cat allergen levels.
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| 5. |
- Jacquemin, B, et al.
(author)
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Association between modelled traffic related air pollution (NO2) and asthma score in ECHRS.
- 2009
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In: European Respiratory Journal. - : The European Respiratory Society. - 0903-1936 .- 1399-3003. ; 34:4, s. 834-842
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Journal article (peer-reviewed)abstract
- The aim of this analysis is to study the association between air pollution and asthma among adults. For this goal, a previously developed "asthma score" was used.Persons aged 25-44 years were randomly selected (1991-1993) and followed up (2000-2002) within the European Community Respiratory Health Survey (ECRHS-I and II). The asthma score was defined from 0 to 5, based on positive answers to symptoms reported for the last 12 months: wheeze/breathlessness, chest tightness, dyspnoea at rest, dyspnoea after exercise, and woken by dyspnoea. Participants' home addresses were linked to outdoor modelled NO2 estimates for 2001. Negative binomial regression was used to model the asthma score.The score from ECRHS-II was positively associated with NO2 (Ratio of the Mean asthma Score (RMS) 1.23, 95% Confidence Intervals (CI): 1.09-1.38 for an increase of 10 microg.m(-3)). After excluding participants with asthma and symptoms at baseline, the association remained (RMS 1.25, 95%CI: 1.05-1.51) and was particularly high among those reporting a high score in ECRHS-II. The latter probably reflects incident cases of asthma.Our results suggest that traffic-related pollution causes asthma symptoms and possibly asthma incidence in adults. The asthma score offers an alternative to investigate the course and aetiology of asthma in adults.
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| 6. |
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| 7. |
- Viana, M., et al.
(author)
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Source apportionment of ambient PM2.5 at five Spanish centres of the European Community Respiratory Health Survey (ECRHS II)
- 2007
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 41:7, s. 1395-1406
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Journal article (peer-reviewed)abstract
- Fine particulate matter (PM2.5) was sampled at 5 Spanish locations during the European Community Respiratory Health Survey II (ECRHS II). In an attempt to identify and quantify PM2.5 sources, source contribution analysis by principal component analysis (PCA) was performed on five datasets containing elemental composition of PM2.5 analysed by ED-XRF. A total of 4-5 factors were identified at each site, three of them being common to all sites (interpreted as traffic. mineral and secondary aerosols) whereas industrial sources were site-specific. Sea-salt was identified as independent source at all coastal locations except for Barcelona (where it was clustered with secondary aerosols). Despite their typically dominant coarse grain-size distribution, mineral and marine aerosols were clearly observed in PM2.5. Multi-linear regression analysis (MLRA) was applied to the data, showing that traffic was the main source of PM2.5 at the five sites (39-53% of PM2.5, 5.1-12.0 mu g m(-3)), while regional-scale secondary aerosols accounted for 14-34% of PM2.5 (2.6-4.5 mu g m(-3)), mineral matter for 13-31% (2.4-4.6 mu g m(-3)) and sea-salt made up 3-7% of the PM2.5 mass (0.4-1.3 mu g m(-3)). Consequently, despite regional and climatic variability throughout Spain, the same four main PM2.5 emission sources were identified at all the study sites and the differences between the relative contributions of each of these sources varied at most 20%. This would corroborate PM2.5 as a useful parameter for health studies and environmental policy-making, owing to the fact that it is not as subject to the influence of micro-sitting as other parameters such as PM10. African dust inputs were observed in the mineral source, adding on average 4-11 mu g m(-3) to the PM2.5 daily mean during dust outbreaks. On average, levels of Al, Si, Ti and Fe during African episodes were higher by a factor of 2-8 with respect to non-African days, whereas levels of local pollutants (absorption coefficient, S, Pb, Cl) showed smaller variations (factor of 0.5-2).
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| 8. |
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| 9. |
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| 10. |
- Dharmage, S. C., et al.
(author)
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Do childhood respiratory infections continue to influence adult respiratory morbidity?
- 2009
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In: European Respiratory Journal. - : European Respiratory Society (ERS). - 0903-1936 .- 1399-3003. ; 33:2, s. 237-244
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Journal article (peer-reviewed)abstract
- The aim of the present study was to examine the influence of childhood respiratory infections on adult respiratory health. In 1992-1994, the European Community Respiratory Health Survey recruited community based samples of 20-44-yr-old people from 48 centres in 22 countries. Study participants completed questionnaires and underwent lung function testing. On average, 8.9 yrs later, 29 centres re-investigated their samples using similar methods. Mixed effects models comprising an estimate for the random variation between centres were used to evaluate the relevant associations. In total, 9,175 patients participated in both studies, of whom 10.9% reported serious respiratory infections (SRI) before 5 yrs of age and 2.8% reported hospitalisation for lung disease (HLD) before 2 yrs if age. SRI was associated with current wheeze (odds ratio (OR) 1.9, 95% confidence interval (CI) 1.7-2.2), asthma (OR 2.5, 95% CI 2.2-3.1), and lower forced expiratory volume in one second (FEV(1); 89 mL; 95% CI 54-126), forced vital capacity (FVC; 49 mL; 95% CI 8-90) and FEV(1)/FVC ratio (-1.2%; 95% CI -1.8- -0.6). Childhood respiratory infections were also associated with new asthma (OR 1.5, 95% CI 1.03-2.0), new wheeze (OR 1.5, 95% CI 1.0-2.4) and persistent wheeze (OR 2.2, 95% CI 1.4-3.6) but not with a decline in lung function. Similar findings were observed for HDL. These associations were significantly consistent across centres. SRI was associated with lower FEV(1) when excluding ever asthmatics and current wheezers. The impact of early infections was significantly larger in subjects exposed to maternal or active smoking. The impact of childhood respiratory infections on the respiratory system may not only last into adulthood but also influence development and persistence of adult respiratory morbidity.
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| 11. |
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| 12. |
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| 14. |
- Jacquemin, B, et al.
(author)
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Association between annoyance and individuals' values of nitrogen dioxide in a European setting.
- 2008
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In: Journal of epidemiology and community health. - 1470-2738. ; 62:5, s. e12-
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Journal article (peer-reviewed)abstract
- INTRODUCTION: Annoyance caused by air pollution has been proposed as an indicator of exposure to air pollution. The aim of this study was to assess the geographical homogeneity of the relationship between annoyance and modelled home-based nitrogen dioxide (NO2) measurements. METHODS: The European Community Respiratory Health Survey II was conducted in 2000-1, in 25 European centres in 12 countries. This analysis included 4753 subjects (from 37 in Tartu, Estonia, to 532 in Antwerp, Belgium) who answered the annoyance question and with available outdoor residential NO2 (4399 modelled and 354 measured) including 20 cities from 10 countries. Annoyance as a result of air pollution was self-reported on an 11-point scale (0, no disturbance at all; 10, intolerable disturbance). Demographic and socioeconomic factors, smoking status and the presence of respiratory symptoms or disease were measured through a standard questionnaire. Negative binomial regression was used. RESULTS: The median NO2 concentration was 27 microg.m(-3) (from 10 in Umeå, Sweden, to 57 in Barcelona, Spain). The mean of annoyance was 2.5 (from 0.7 in Reykjavik, Iceland, to 4.4 in Huelva, Spain). NO2 was associated with annoyance (ratio of the mean score 1.26 per 10 microg.m(-3), 95% CI 1.19 to 1.34). The association between NO2 and annoyance was heterogeneous among cities (p for heterogeneity <0.001). CONCLUSIONS: Annoyance is associated with home outdoor air pollution but with a different strength by city. This indicates that annoyance is not a valid surrogate for air pollution exposure. Nevertheless, it may be a useful measure of perceived ambient air quality and could be considered a complementary tool for health surveillance.
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| 15. |
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| 16. |
- Künzli, Nino, et al.
(author)
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Comparison of oxidative properties, light absorbance, total and elemental mass concentration of ambient PM2.5 collected at 20 European sites.
- 2006
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In: Environ Health Perspect. - 0091-6765. ; 114:5, s. 684-90
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Journal article (peer-reviewed)abstract
- BACKGROUND: Body mass, as well as distribution of body fat, are predictors of both diabetes and cardiovascular disease. In Northern Sweden, despite a marked increase in average body mass, prevalence of diabetes was stagnant and myocardial infarctions decreased. A more favourable distribution of body fat is a possible contributing factor.This study investigates the relative importance of individual food items for time trends in waist circumference (WC) and hip circumference (HC) on a population level. METHODS: Independent cross-sectional surveys conducted in 1986, 1990, 1994 and 1999 in the two northernmost counties of Sweden with a common population of 250,000. Randomly selected age stratified samples, altogether 2982 men and 3087 women aged 25-64 years. Questionnaires were completed and anthropometric measurements taken. For each food item, associations between frequency of consumption and waist and hip circumferences were estimated. Partial regression coefficients for every level of reported intake were multiplied with differences in proportion of the population reporting the corresponding levels of intake in 1986 and 1999. The sum of these product terms for every food item was the respective estimated impact on mean circumference. RESULTS: Time trends in reported food consumption associated with the more favourable gynoid distribution of adipose tissue were increased use of vegetable oil, pasta and 1.5% fat milk. Trends associated with abdominal obesity were increased consumption of beer in men and higher intake of hamburgers and French fried potatoes in women. CONCLUSION: Food trends as markers of time trends in body fat distribution have been identified. The method is a complement to conventional approaches to establish associations between food intake and disease risk on a population level.
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| 17. |
- Radon, Katja, et al.
(author)
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Occupation and adult onset of rhinitis in the general population
- 2008
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In: Occupational and Environmental Medicine. - : BMJ. - 1351-0711 .- 1470-7926. ; 65:1, s. 38-43
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Journal article (peer-reviewed)abstract
- Objectives: Occupational exposures have been associated with an increased risk of new-onset rhinitis in apprentices. However, population-based prospective data are scarce and do not cover new onset of rhinitis later in life. The authors studied the association between occupational exposure and adult onset of rhinitis prospectively. Methods: The data of 4994 participants (age at follow-up 28-57 years) from 27 centres of the European Community Respiratory Health Survey II who were symptom-free at baseline were analysed. As outcome at follow-up self-reported (a) nasal allergies ("allergic rhinitis'') and (b) runny, blocked nose for 12 months a year ("perennial rhinitis'') were used. Occupational exposures at any time during follow-up were defined by job title. Results: The cumulative incidence of allergic rhinitis, perennial rhinitis and both conditions was 12%, 11% and 3%, respectively. Compared to office workers, male medical professionals were at increased risk of new onset of allergic rhinitis (OR 3.0; 95% CI 1.4 to 6.4). Odds ratios were reduced in metal workers not involved in metal making or treating (0.3; 95% CI 0.1 to 0.7). For perennial rhinitis ORs were significantly increased in cleaners (1.4; 95% CI 1.0 to 2.1). Conclusions: Cleaners and medical professionals may be at increased risk for adult-onset rhinitis.
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| 18. |
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| 19. |
- Bedada, G. B., et al.
(author)
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Urban background particulate matter and allergic sensitization in adults of ECRHS II
- 2007
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In: Int J Hyg Environ Health. - : Elsevier BV. - 1438-4639. ; 210:6, s. 691-700
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Journal article (peer-reviewed)abstract
- BACKGROUND: Epidemiological studies have shown weak or inconsistent associations between ambient air pollutants and allergic sensitization. The aim of this study was to evaluate whether regional urban air pollution may partly explain the large variation in the prevalence of allergic sensitization across cities of the European Community Respiratory Health Survey (ECRHS) II. METHODS: ECRHS is a cross-sectional survey initiated in 29 countries across Europe in the 1990s (ECRHS I) with a follow-up conducted 10 years later (ECRHS II). Subject characteristics were measured by questionnaires and blood tests conducted for the measurement of specific immunoglobulin E. Fine particle mass (PM(2.5), <2.5mum) and sulphur on PM(2.5) were measured in 21 centres and annual averages of urban regional background air pollution were calculated. Results were scaled by an interquartile range increase in ambient PM(2.5) (6.03mug/m(3)) and sulphur (1336ng/m(3)). Generalized estimating equations were applied to compute population average effect estimates with adjustment for age, gender, smoking habit, education and number of siblings. RESULTS: A notable variation in pollution level and prevalence of allergic sensitization was observed. Moreover, exposure to urban regional background air pollution was not associated with allergic sensitization; adjusted odds ratios and 95% confidence interval were 1.02 (0.95-1.09) for PM(2.5) and 1.08 (0.86-1.31) for sulphur. These statistically non-significant associations were sensitive to model specification. CONCLUSIONS: The study suggests that regional air pollution measured at fixed sites is not associated with allergic sensitization among adults in ECRHS II.
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| 20. |
- Echtermeyer, Tim J., et al.
(author)
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Nonvolatile switching in graphene field-effect devices
- 2008
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In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 29:8, s. 952-954
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Journal article (peer-reviewed)abstract
- The absence of a band gap in graphene restricts its straightforward application as a channel material in field-effect transistors. In this letter, we report on a new approach to engineer a band gap in graphene field-effect devices (FEDs) by controlled structural modification of the graphene channel itself. The conductance in the FEDs is switched between a conductive "ON-state" and an insulating "OFF-state" with more than six orders of magnitude difference in conductance. Above a critical value of an electric field applied to the FED gate under certain environmental conditions, a chemical modification takes place to form insulating graphene derivatives. The effect can be reversed by electrical fields of opposite polarity or short current pulses to recover the initial state. These reversible switches could potentially be applied to nonvolatile memories and novel neuromorphic processing concepts.
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| 26. |
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| 27. |
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| 28. |
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| 29. |
- Jacquemin, B., et al.
(author)
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Annoyance due to air pollution in Europe
- 2007
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In: Int J Epidemiol. - : Oxford University Press (OUP). - 0300-5771 .- 1464-3685. ; 36:4, s. 809-20
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Journal article (peer-reviewed)abstract
- BACKGROUND: Annoyance due to air pollution is a subjective score of air quality, which has been incorporated into the National Environmental monitoring of some countries. The objectives of this study are to describe the variations in annoyance due to air pollution in Europe and its individual and environmental determinants. METHODS: This study took place in the context of the European Community Respiratory Health Survey II (ECRHS II) that was conducted during 1999-2001. It included 25 centres in 12 countries and 7867 randomly selected adults from the general population. Annoyance due to air pollution was self-reported on an 11-point scale. Annual mean mass concentration of fine particles (PM(2.5)) and its sulphur (S) content were measured in 21 centres as a surrogate of urban air pollution. RESULTS: Forty-three per cent of participants reported moderate annoyance (1-5 on the scale) and 14% high annoyance (>/=6) with large differences across centres (2-40% of high annoyance). Participants in the Northern European countries reported less annoyance. Female gender, nocturnal dyspnoea, phlegm and rhinitis, self-reported car and heavy vehicle traffic in front of the home, high education, non-smoking and exposure to environmental tobacco smoke were associated with higher annoyance levels. At the centre level, adjusted means of annoyance scores were moderately associated with sulphur urban levels (slope 1.43 mug m(-3), standard error 0.40, r = 0.61). CONCLUSIONS: Annoyance due to air pollution is frequent in Europe. Individuals' annoyance may be a useful measure of perceived ambient quality and could be considered a complementary tool for health surveillance.
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| 30. |
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| 31. |
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| 32. |
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| 33. |
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| 34. |
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| 35. |
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| 36. |
- Lemme, Max C., 1970-, et al.
(author)
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A graphene field-effect device
- 2007
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In: IEEE Electron Device Letters. - 0741-3106 .- 1558-0563. ; 28:4, s. 282-284
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Journal article (peer-reviewed)abstract
- In this letter, a top-gated field-effect device (FED) manufactured from monolayer graphene is investigated. Except for graphene deposition, a conventional top-down CMOS-compatible process flow is applied. Carrier mobilities in graphene pseudo-MOS structures are compared to those obtained from the top-gated Graphene-FEDs. The extracted values exceed the universal mobility of silicon and silicon-on-insulator MOSFETs.
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| 37. |
- Nawrot, Tim S, et al.
(author)
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Oxidative properties of ambient PM2.5 and elemental composition : heterogeneous associations in 19 European cities
- 2009
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In: Atmospheric Environment. - : Elsevier BV. - 1352-2310 .- 1873-2844. ; 43:30, s. 4595-4602
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Journal article (peer-reviewed)abstract
- We assessed the extent to which constituents of PM2.5 (transition metals, sodium, chloride) contribute to the ability to generate hydroxyl radicals (OH) in vitro in PM2.5 sampled at 20 locations in 19 European centres participating in the European Community Respiratory Health Survey. PM2.5 samples (n = 716) were collected on filters over one year and the oxidative activity of particle suspensions obtained from these filters was then assessed by measuring their ability to generate OH in the presence of hydrogen peroxide. Associations between OH formation and the studied PM constituents were heterogeneous. The total explained variance ranged from 85% in Norwich to only 6% in Albacete. Among the 20 centres, 15 showed positive correlations between one or more of the measured transition metals (copper, iron, manganese, lead, vanadium and titanium) and OH formation. In 9 of 20 centres OH formation was negatively associated with chloride, and in 3 centres with sodium. Across 19 European cities, elements which explained the largest variations in OH formation were chloride, iron and sodium.
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| 38. |
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| 39. |
- Vangeyte, P., et al.
(author)
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Adsorption of poly(ethylene oxide)-b-poly(is an element of-caprolactone) copolymers at the silica-water interface
- 2005
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In: Langmuir. - : American Chemical Society (ACS). - 0743-7463 .- 1520-5827. ; 21:7, s. 2930-2940
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Journal article (peer-reviewed)abstract
- The adsorption of amphiphilic poly(ethylene oxide)-b-poly(epsilon-caprolactone) and poly(ethylene oxide)-b-poly(gamma-methyl-epsilon-caprolactone) copolymers in aqueous solution on silica and glass surfaces has been investigated by flow microcalorimetry, small-angle neutron scattering (SANS), surface forces, and complementary techniques. The studied copolymers consist of a poly(ethylene oxide) (PEO) block of M-n, = 5000 and a hydrophobic polyester block of poly(E-caprolactone) (PCL) or poly(gamma-methyl-epsilon-caprolactone) (PMCL) of M-n in the 950-2200 range. Compared to homoPEO, the adsorption of the copolymers is significantly increased by the connection of PEO to an aliphatic polyester block. According to calorimetric experiments, the copolymers interact with the surface mainly through the hydrophilic block. At low surface coverage, the PEO block interacts with the surface such that both PEO and PCL chains are exposed to the aqueous solution. At high surface coverage, a dense copolymer layer is observed with the PEO blocks oriented toward the solution. The structure of the copolymer layer has been analyzed by neutron scattering using the contrast matching technique and by tapping mode atomic force microscopy. The experimental observations agree with the coadsorption of micelles and free copolymer chains at the interface.
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